Electromagnetic sound reproducer



Sept. 18, 1928.

W. H. GERNS ELECTROMAGNETIC SOUND REPRODUCER Filed March 12, 1927 3Sheets-Sheet IE- E INVENTOR. z f/z'am #6267726,

W A TTORNEY Sept. 18, 1928. 1,685,050

w. H. GERNS ELECTROMAGNETI C SOUND REPRODUCER Filed March 12, 1927 5Sheets-Sheet 2 INVENTOR.

6 0 ATTORNEY.

Sept. 18, 1928. 1,685,050

w. H. GERNS ELECTROMAGNETI C SOUND REPRODUCER Filed March 12, 1927 5Sheets-Sheet 3 \okxif V a W INVEN TOR. W afia ez'jze,

d u a A TORNEY.

Patented Sept. 18, 1928.

UNITED STATES- 1,685,050 PATENT OFFICE.

WILLIAM H. GERNS, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO BRANDESLABORA- TORIES, INC., 01 NEWARK, NEW JERSEY, A CORPORATION OF NEWJERSEY.

ELECTROMAGNETIC SOUND REPRODUCER.

Application filed March 12, 1927. Serial No. 174,869.

My invention relates broadly to broadcast receiving apparatus and moreparticularly to a loud speaker reproducer system for broadcast receivingapparatus.

5 One of the objects of my invention is to provide a construction ofloud speaker reproducer which may be readily mounted within a cabinetwith associated radio receiving apparatus for eflicient reproduction ofsound without interference from mechanical shock and vibration.

Another object of my invention is to provide a mounting for a loudspeaker reproducer within a cabinet structure with means for insulatingthe loud speaker reproducer from interference occasioned by mechanicalshock or vibrations which normally tend to introduce microphonic noisesinto the reproducer and thereby detrimentally affect the soundreproduction.

Another object of my invention is to provide a construction of cone typesound reproducer which may be removably mounted within a broadcastreceiver cabinet in association with radio receiving apparatus andacoustically insulated against interference from microphonic noises setup adjacent the sound reproducer.

Another object of my invention is to provide a construction ofelectromagnetic sound reproducer which may be suspended from ashelf-like frame arranged to be moved horizontally into or withdrawnfrom a radio receiving apparatus cabinet structure, the shelflike framebeing acoustically insulated from the cabinet structure for preventinginterference from microphonic noises and limiting acoustic feed back inthe receiving apparatus.

Still another object of my invention is to provide a construction ofloud speaker system for cabinet type radio broadcast receivers by whichthe production and assembl of a cabinet type receiver can be facilitatedy the insertion of the loud speaker system into a compartment of thecabinet or the removal of the loud speaker therefrom for connection withthe output of the radio receiving apparatus.

My invention will be more fully understood from the followingspecification by reference to the accompanying drawings, in which Figure1 is a front view of the loud speaker system shown in position withinthe radio receiving apparatus cabinet structure; Fig. 2 is a lateralcross-sectional view taken through view showing the electromagneticsound reproducer and the bracket members by which the sound reproducermay be slidabl supported within the cabinet structure; Fig. 6 isa planview of the loudspeaker system showing the loud speaker partiallyremoved from the cabinet structure; and Fig. 7 is a crosssectional viewof the loud speaker as repre sented in Fig. 6 showing the loud speakerbeing removed from the apparatus cabinet.

in mounting a loud speaker sound reproducer within a cabinet whichhouses associated radio receiving apparatus, there is a tendency forinicrophonic noises to be reproduced bythe loud speaker due tomechanical shock and vibration which may arise in different parts of theradio receiving apparatus. In sound reproducei's of extreme sensitivity,there is a tendency for acoustic feed back in the circuits of theelectron tubes to produce a continuous roar or hum in the loud speakerwhich seriously interferes with quality reception. I have developed thepresent construction for the removable mounting of an electromagnet csound reproducer within a cabinet structure with means for eliminatingthe undesirable acoustic feed back for insuring quality reproductionindependently of shock or vibration which may occur in parts of theradio receiving apparatus adjacent to the loud speaker sound reproducer.

Referring to the drawings in detail reference character 1 designates acabinet housing in which the radio receiving apparatus is mounted indifferent compartments. The doors 2 are shown in open position, thesedoors normally serving to close the front of the cabinet housing forentirely enclosing the radio receiving apparatus and loud speakerreproducer. An ornamental panel 3 is provided serving to close thecompartment in the cabinet 1 which is provided for the mounting of theelectromagnetic sound reproducer. The panel 3 is removable from thefront of the cabinet 1 to allow the insertion or removal of the loudspeaker from the cabinet housing. An aperture 4 is provided in the panel3 through which sound emanates from the loud speaker within the cabinet.The loud speaker is mounted from the laterally extending shelf member 5by means of a pair of bracket members 6 and 7 into which the frame ofthe loud speaker is arranged to slide. The loud speaker frame includes ashelf-like member 8 to which the plate member 9 is connected and fromwhich the electromagnetic sound reproducer 23 is suspended by means ofthe bracket member 22. The plate member 9 is centrally apertured at 10and within this apertured portion, the peripheral edge of the coneshaped sound reproducing diaphragm 11 is free to float. A damping ring12 is provided around the peripheral edge of the cone 11, this dampingring being connected to the rear surface of the panel 9.

The brackets 6 and 7 which provide supporting means for the cone, eachconsist of pressed channel members having an end portion 15 which formsan abutment or stop for the end of the shelf 8. Each channel member hasan integrally connected lug portion 16 formed thereon and from the lugportion 16, a screw threaded stud member 14 extends. The brackets 6 and7 are so positioned on the lower surface of the shelf 5 that the screwthreaded stud member 14 may protrude through apertures 19 in the plate 9when the loud speaker is moved into the cabinet housng 1. The plate 9 isprovided with finger holes 20 to facilitate the insertion or removal ofthe loud speaker from the brackets 6 and 7. The edges of the shelf-likeportion 8 are substantially covered with felt or other sound insulatingmaterial, the felt serving to acoustically insulate the loud speakersystem from the radio receiving apparatus cabinet or the radio receivingapparatus which is mounted within the cabinet. It will be observed thatthe felt 21' entirely covers the ends of the rear edge of the shelf 8 sothat direct abutment between the shelf 8 and the limiting stops 15 onthe brackets is prevented. In order to further acoustically insulate theloud speaker system from the cabinet structure, I provide large feltwashers 17 and 18 which fit over the screw threaded studs 14 on oppositesides of the plate member 9 and provide sound insulating abutmentsagainst which the nut 25 may operate. Bracket members 24 extend betweenthe rear of the plate member 9 and the shelf 8 for mechanicallyreinforcing the loud speaker assembly.

The construction of loud speaker system herein greatly facilitatesmanufacture and assembly of radio receiving apparatus with built-in loudspeakers. The cabinet structure in which the broadcast apparatus ishoused may include a number of different compartments, one compartmentserving to enclose the radio receiving apparatus while othercompartments are provided for the power supply equipment and the soundreproducer. The complete loud speaker may be tested and then moved intoplace for connection with the output circuit of the receiving apparatusthrough flexible conductor 26 with a knowledge that the combinedequipment is complete and may be shipped ready for installation withminimum effort on the part of the purchaser of the equipment.

For the purposes of illustrating my invention, I have shown anelliptically shaped sound reproducing diaphragm but my invention isequally applicable to diaphragm of various shapes and sizes, andcircular constructions of cones may be employed in a manner as equallysatisfactory as the elliptical shaped cone shown in the drawings.

It will also be understood that while the drawings show the loud speakercompartment as a part of a radio receiver cabinet, the loud speaker ofmy invention may be mounted in an independent cabinet as part of apublic address system or voice reproducer used with a variety of kindsof apparatus such as a talkin film system.

Vhile I have described the preferred embodiment of my invention, Idesire it to be understood that modifications and improvements may bemade within the scope of the appended claims without departing from thespirit of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is as follows:

1. In a radio cabinet a loud speaker construction comprising ashelf-like support, an electromagnetic driver depending from saidshelf-like support, a sound reproducing diaphragm connected with saidelectromagnetic driver and a pair of brackets within said radio cabinetspaced from each other in the same plane above the normal position ofsaid driver for slidably mounting said shelf-like support within saidradio cabinet.

2. A radio cabinet comprising a laterally extending shelf member, a pairof bracket members mounted beneath said laterally extendin shelf memberand adjacent opposite ends thereof a frame member arranged to beslidably mounted within said bracket members and an electromagneticdriver carried by said frame member for actuating a sound reproducingdiaphragm positioned within said radio cabinet and supported by saidframe member.

3. A radio cabinet structure including a loud speaker compartment, apair of bracket members mounted from the top portion of said compartmentadjacent opposite ends thereof, a shelf-like frame structure comprisinga pair of independent panels, one of said panels being slidably mountedin said bracket members, an electromagnetic sound reproducer carried byone panel of said shelf-like frame structure,"a sound reproducingdiaphragm supported by the other panel of said frame structure, saidshelf-like frame structure being movable from a position entirely withinsaid compartment to a position outside of said compartment for repairand adjustment of said electromagnetic sound reproducer.

4. A radio cabinet structure including a loud speaker compartment, apair of bracket members mounted in said loud speaker compartment, a loudspeaker including a shelflike frame adapted to slidably engage saidbracket members, a sounding board carried by said frame and extending atright angles thereto, a sound reproducing diaphragm carried by saidsounding board, said shelf-like frame being movable from a positionentirely enclosed by said cabinet structure to a posit'ion outside ofsaid cabinet structure, and means interposed between each of saidbracket members and the ends of said shelflike frame for acousticallyinsulating said loud speaker from said radio cabinet structure.

5. A loud speaker cabinet comprising an acoustic chamber, anelectromagnetic sound reproducer, a frame for supporting saidelectromagnetic sound reproducer, and means in said acoustic chamber forremovably suspending the frame of said electromagnetic sound reproducerin a position within said acoustic chamber, and guide members forcontrolling the removal and replacement of said frame with respect tosaid chamber.

6. A loud speaker construction comprising an acoustic chamber, a framestructure, an electromagnetic driver carried by said frame structure, asounding board depending from said frame structure, a sound reproducingdiaphragm connected to said electromagnetic driver and carried by saidsounding board, and means for removably securing said frame structurewithin said acoustic chamber whereby said frame structure may bepositioned within said acoustic chamber or displaced to a positionoutside of said acoustic chamber by movement of said frame structure ina substantially horizontal plane.

7. A loud speaker including an acoustic chamber, a slidable framestructure having one side thereof removably engaging one side of saidacoustic chamber, an electromagnetic driver carried by said framestructure, a sounding board extending at right angles to said framestructure, a sound reproducing diaphragm carried by said sounding boardand actuated by said electromagnetic driver, said electroma etic driverand sound reproducing diap ragm being movable from a position withinsaid acoustic chamber to a osition displaced from said acoustic chamr,and acoustic insulation material surrounding the ends of said framestructure and acoustically insulating said frame structure from saidacoustic chamber.

8. A loud speaker comprising an acoustic chamber, a frame structureslidably mounted Within said acoustic chamber, said frame structureincluding a shelf-like laterally extending member and a vertical platemember extending substantially at right angles to said shelf-likemember, an electromagnetic driver depending from said shelf-like member,a sound reproducing diaphragm actuated by said electromagnetic driver,said diaphragm having its peripheral edge terminating in the plane ofsaid vertical plate member, said vertical plate member substantiallyclosing the front of said acoustic chamber when said frame structure ismoved to a position within said acoustic chamber from the front thereof.

9. A loud speaker comprising an acoustic chamber, a frame structureincluding slidable member having a sounding board extendingsubstantially at right angles thereto, sound insulating materialsubstantially covering opposite edges of said slidable member, a pair ofbrackets carried by one side of said acoustic chamber, said bracketsbeing arranged to slidably engage the opposite edges of said slidablemember, an electromagnetic driver depending from said slidable member, asound reproducing diaphragm actuated by said electromagnetic driver andhaving its peripheral edge terminating in the plane of said soundingboard below said slidable member, said sounding board serving tosubstantially enclose the front of said acoustic chamber when said framestructure is moved to a position within said acoustic chamber from thefront thereof.

10. A loud speaker comprising an acoustic chamber, a frame structureincluding a pair of flat members disposed substantially at right anglesto each other, one of said flat members providing a depending supportfor an electromagnetic driver, a sound reproducing diaphragm connectedwith said electromagnetic driver and having its peripheral edgeterminating in the plane of the other of said flat members, meanscarried by said acoustic chamber for slidably mounting said framestructure therein for movement in a horizontal plane, and sound proofmaterial enveloping the edges of one of said flat members foracoustically insulating said frame structure from said acoustic chamberthroughout the range of movement of said frame structure in a horizontalplane.

11. A loud speaker comprising an acoustic chamber, a pair of bracketmembers carried by one side of said acoustic chamber, stud membersextending from each of said bracket members, a frame structure includingportions extending substantially at right angles to each other, anelectromagnetic driver depending from one of said portions, a soundreproducing diaphragm connected with said electromagnetic driver andhavin its peripheral edge terminating in the pfane of the other of saidportions of said frame structure, the first mentioned portion of saidframe structure being slidable from a position displaced from saidbracket members toa position Within said cabinet structure Where saidstud members project through the last mentioned portion of said framestructure for securing said frame structure in a position on said studmembers enclosed by said acoustic chamber.

12. A loud speaker comprising an acoustic chamber, a pair of bracketmembers carried by one side of said acoustic chamber, stud membersextending from each of said bracket members, a frame structure includingportions extending substantially at right angles to each other, anelectromagnetic driver depending from one of said portions, a soundreproducing diaphragm connected with said elcctromagnetc driver andhaving its peripheral edge terminating in the plane of the other of saidportions of said frame structure, said last mentioned portion beingshaped to substantially close the front of said acoustic chamber, andthe first mentioned portion of said frame structure being slidable insaid bracket members to aposition displaced from said acoustic chamberto a position within said acoustic chamber Where said stud membersproject through said frame structure for securing said frame structurein position with respect to said chamber.

13. A loud speaker comprising an acoustic chamber, bracket memberscarried by one side of said acoustic chamber, screw threaded studmembers extending from said bracket mem bers, a frame structure havingportions extending at right angles with respect to each other, anelectromagnetic driver suspended from one of said portions and having asound reproducing diaphragm connected thereto, with the peripheral edgeof said diaphragm terminating in the plane of another portion of saidframe structure, the edges of the first mentioned portion of said framestructure being provided with sound insulating pads for sliclablyengaging said bracket members when said loud speaker is moved to aposition Within said acoustic chamber with said studs projecting througha portion of said frame structure, pads of acoustically insulatedmaterial disposed between said studs and said frame structure and nutsengaging said studs for locking said frame structure in position on saidstuds within said acoustic chamber.

ln testimony whereof I aflix my signature.

WILLIAM H. GERNS.

